CD72 is a pan-tumor antigen associated to pediatric acute leukemia

In the development of novel immunotherapeutic approaches, the step of target identification is a challenging process, because it aims at identifying robust tumor-associated antigens (TAAs) specific for the pathological population and causing no off-target effects. Here we propose CD72 as a novel and robust TAA for pediatric acute leukemias. We provided an outline of CD72 expression assessed by flow cytometry on a variety of cancer cell lines and primary samples, including normal bone marrow (BM) samples and hematopoietic stem and progenitor cells. We analyzed CD 72 expression on a cohort of 495 pathological pediatric BM aspirates, including: 215 B-cell precursor acute lymphoblastic leukemias (BCP-ALL), 156 acute myeloid leukemias (AMLs), 88 T-lineage ALLs or lymphoblastic lymphomas with BM infiltration, 13 B-lineage lymphoblastic lymphomas with BM infiltration, 9 myelodysplastic syndromes with increased blasts (5%-9% blasts on BM: MDS-IB1) and 14 non-hematopoietic solid tumors infiltrating BM. Results showed that CD72 is highly expressed in almost all BCP-ALL and the majority of AML at diagnosis, including BCP-ALL cases characterized by CD19 loss. These findings support a potential role for advanced diagnostics and novel immunotherapy approaches, providing a pan-ALL and AML target.

Lentiviral hematopoietic stem cell gene therapy in patients with Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is an inherited immunodeficiency caused by mutations in the gene encoding WASP, a protein regulating the cytoskeleton. Hematopoietic stem/progenitor cell (HSPC) transplants can be curative, but, when matched donors are unavailable, infusion of autologous HSPCs modified ex vivo by gene therapy is an alternative approach. We used a lentiviral vector encoding functional WASP to genetically correct HSPCs from three WAS patients and reinfused the cells after a reduced-intensity conditioning regimen. All three patients showed stable engraftment of WASP-expressing cells and improvements in platelet counts, immune functions, and clinical scores. Vector integration analyses revealed highly polyclonal and multilineage haematopoiesis resulting from the gene-corrected HSPCs. Lentiviral gene therapy did not induce selection of integrations near oncogenes, and no aberrant clonal expansion was observed after 20 to 32 months. Although extended clinical observation is required to establish long-term safety, lentiviral gene therapy represents a promising treatment for WAS.

NGRhTNF, a new vascular targeting agent with a dual mechanism of action: preliminary clinical results

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Background: NGRhTNF is a vascular targeting agent (VTA) exploiting a tumour homing peptide (CNGRCG) selectively binding solid tumor (lung, renal, and colorectal) neovasculature. NGRhTNF specific binding relies on dynamic interactions with TNF-receptors, aminopeptidase N (CD13) and a specific integrin: a combination of receptors expressed by the tumor neovasculature endothelium, but not on normal vessels. This combination provides NGRhTNF with unique biological properties: at low dose, increased tumor vascular permeability, and massive tumor necrosis at high dose. Mouse preclinical data confirmed these properties, revealing also strong synergy between low dose NGRhTNF and cytotoxic agents (antracyclines, platinum based compounds, etc.). Methods: Based on these data, a series of studies were designed. A multicentre phase I study with NGRhTNF as single agent -still in progress- aims at defining MTD and preliminary anticancer activity, within the EORTC network (EORTC 16041). A single center phase I study exploiting the low dose range (0.2–1.6 μg/m2) aims at defining safety and NGRhTNF activity on the tumor vascular permeability using DCE MRI (HSR NGR002). Results: Twelve advanced neoplastic patients were enrolled in the HSR NGR002 study. Up to the dose of 1.6 μg/m2, the only common toxicity was represented by constitutional symptoms such as infusion-associated chills (40%) of mild to moderate intensity. At the tested doses, NGRhTNF increased vascular permeability, as shown by changes in DCE MRI parameters (Ktrans and Kep), and modulated the expression of chemokines possessing antiangiogenic activity. NGRhTNF achieved stable disease in about 45% of highly refractory treated patients, and still ongoing long lasting disease control in 2 cases (7 and 9 months along with sharp decline of CA125 and VEGF). Conclusions: NGR-hTNF, a VTA with a unique mechanism of action, combines activity on tumor vascular permeability and direct anti-cancer effect. Preliminary data in humans confirm its favourable safety profile along with remarkable anticancer activity, thus rendering the agent suitable for a development program alone or in combination with chemotherapeutics. Phase II low dose combination studies will begin in 2006.

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Acute HIV infection: impact on the spread of HIV and transmission of drug resistance

OBJECTIVE

To assess the impact of primary HIV infection (PHI) on the spread of HIV and the temporal trends in transmission of HIV drug resistance between 1996 and 1999 in Switzerland.

METHODS

Sequencing of the genes for reverse transcriptase (RT) and protease was performed for 197 individuals with documented PHI. Phylogenetic analyses were confronted with epidemiological data.

RESULTS

Significant clustering was demonstrated for 29% of the RT sequences. All these cases occurred closely together in place and time; contact tracing demonstrated transmission at the time of PHI in 30% of them. Genotypic drug resistance was detected in 8.6% of PHI individuals in 1996, 14.6% in 1997, 8.8% in 1998 and 5.0% in 1999. Drug-resistant variants were identified in 11.3% of individuals infected by homosexual contacts, 6.1% by heterosexual contacts, 13% of intravenous drug users and more frequently in men (10.4%) than women (2.6%). Potential factors involved in the recent decrease of transmission of drug-resistant variants include increase of HIV non-B subtypes from 23% in 1996 to 35% in 1999 (only one non-B subtype had resistance mutations) and a steady increase of patients with undetectable viraemia as documented in Swiss HIV Cohort Study (10% in 1996 vs 53% in 1999).

CONCLUSIONS

Phylogenetic and epidemiological analyses underline the impact of PHI in the spread of HIV. Moreover, this study indicates that drug resistance transmission may have decreased recently in Switzerland through the increased frequency of infection with HIV non-B subtypes and the steady increase of patients with undetectable viraemia.

Sampling lymphoid tissue cells by ultrasound-guided fine needle aspiration of lymph nodes in HIV-infected patients. Swiss HIV Cohort Study

OBJECTIVE

To establish the feasibility of using ultrasound-guided lymph node needle aspiration as a means to obtain lymphoid tissue cells for the determination of a series of immunologic and virologic measures in HIV-infected patients.

DESIGN

First, a comparison of the characteristics of cell populations obtained by simultaneous needle aspiration and standard excisional biopsy in six patients. Second, use of lymph node needle aspiration to assess longitudinally T-cell subset changes in patients initiating highly effective antiretroviral treatment.

METHODS

T-cell subsets (CD4 and CD8) and percentage Ki67+ cycling T cells were measured in lymph node cell populations harvested by ultrasound-guided aspiration or standard biopsy by flow cytometry. Cellular RNA content was assessed by a modification of the Roche Amplicor HIV-1 Monitor test.

RESULTS

CD4 and CD8 T-cell percentage and HIV RNA cell content of lymph node cell suspensions obtained from the simultaneous performance of ultrasound-guided needle aspiration and excisional biopsy in the same patients were correlated (n = 6). Among the 87 aspiration sessions reported here, mononuclear cell suspensions were obtained in 100% of the sessions, in numbers ranging between 4x10(4) to 6.7x10(6) cells (median: 7x10(5)). This limited number of cells did not allow to perform all type of analyses in all patients. By prioritizing the cells for the determination of T-cell subsets and proliferation rate, this approach was instrumental for demonstrating the normalization of the T-cell subset ratio and the kinetic of normalization of proliferating rates of CD4 and CD8 T cells, as well as the decrease in HIV-1 viral load in the lymph node following HAART initiation.

CONCLUSION

Ultrasound-guided aspiration appears to be a non-invasive and ad libitum, safe and repeatable procedure for the longitudinal monitoring of changes in lymph nodes.

Prevalence and causes of visual impairment in Italy

This Italian study, based on the National Household Health Survey (NHHS), the Registry of the Blind and the Welfare lists of the Ministry of the Interior, was designed to estimate the prevalence of blindness and hypovision in Italy and describe its geographical distribution. In addition, a national sample of 29 763 Registry members was studied to describe causes of blindness. The prevalence from NHHS data was 4.3 per 1000 in 1983 and 4.5 in 1986-1987 (3.2 in the North, 4.6 in the Centre, 6.5 in the South). Welfare recipients were 112,783 in 1988, a prevalence of 2.0 per 1,000, but were fewer in Northern than in Southern regions (range 0.7-4.8). The Registry of the Blind had 80,918 members in 1984 (prevalence 1.4 per 1,000) and 106,000 in 1989 (prevalence 1.9): < 1 per 1,000 in the North and > 3 in the South. The most frequent causes of blindness among Registry members were retinal diseases (33%) and cataract (23%). The causes of preventable blindness were more frequently reported in Southern than in Northern Italy.